From: "Ron Larock" <rlarock@mediaone.net>
Subject: COZY: foam cores
Date: Thu, 25 Mar 1999 18:38:21 -0500

I know that cutting cores with a hot wire is 
very accurate, but I would think that finding new and possibly more accurate 
ways of doing things is also what we are about. If a lazer can cut the foam to a 
much higher degree of accuracy and faster, maybe this group may have found a way 
to make building composite airplanes faster and cheaper. It may bring others 
that aren't as mechanical into the airplane building business. It may also find 
its way into a factory built composite that is affordable to a larger group of 
people.From ???@??? Thu Mar 25 21:15:02 1999
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From: Todd Carrico <todd.carrico@aris.com>
To: "'Nat Puffer'" <cozy@extremezone.com>, All <Cozy_Builders@canard.com>
Subject: RE: COZY: Laser cut foam cores
Date: Thu, 25 Mar 1999 14:41:21 -0800
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Reply-To: Todd Carrico <todd.carrico@aris.com>
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Oh, I would not buy such a machine.  My experience with this sort of thing
is that by the time you get it setup, you could have done the job by hand.
If you are making ten of them, then maybe it would be worth it (make sure
you buy ten copies of the plans <grin>), you also would not need a helper.

I have plenty of help, and not plenty of money ;)

tc

-----Original Message-----
From: Nat Puffer [mailto:cozy@extremezone.com]
Sent: Thursday, March 25, 1999 2:25 PM
To: Todd Carrico; All
Subject: Re: COZY: Laser cut foam cores


Todd,
Where is your pride, your joy of accomplishment, the satisfaction of your
urge to be creative, your self esteem? You miss all the fun if you have
someone else do all the work. You might as well buy a factory built!
Best regards,
Nat


----------
> From: Todd Carrico <todd.carrico@aris.com>
> To: All <Cozy_Builders@canard.com>
> Subject: RE: COZY: Laser cut foam cores
> Date: Thursday, March 25, 1999 11:19 AM
> 
> Price was $1550.00 US.  that was with a 40" cutting width.  Bigger tables
on
> request.  I don't know about modifying it for longer pieces.  He said
that
> it would put in Wash Out/in, taper, sweep.  Would work for turtle decks,
> julian fries, etc.
> 
> tc
> 
> -----Original Message-----
> From: Bill Theeringer
> [mailto:Composite_Aircraft_Accessories@compuserve.com]
> Sent: Wednesday, March 24, 1999 11:36 PM
> To: All
> Subject: COZY: Laser cut foam cores
> 
> 
> Check out http://www.teeka.com/cbhobby/
> for precut foam cores :)=
> 
> Bill T.

From: cdenk@ix.netcom.com
Date: Thu, 25 Mar 1999 17:12:37 -0600 (CST)
Subject: RE: COZY: Laser cut foam cores

was said <Price was $1550.00 US.  >

I can't see where there is any major time savings, hot wiring is easy, the equipment can be had for around $100, and many 
times can be borrowed. A very large pecentage of the EZ's flying, the builder's personally had there hands on the process, 
with just fine results.

Date: Thu, 25 Mar 1999 17:51:52 -0600
From: Tom Brusehaver <tgb@cozy.core.wamnet.com>
Subject: Re: COZY: foam cores


>I know that cutting cores with a hot wire is very accurate, but I would =
>think that finding new and possibly more accurate ways of doing things =
>is also what we are about. If a lazer can cut the foam to a much higher =
>degree of accuracy and faster, maybe this group may have found a way to =
>make building composite airplanes faster and cheaper. It may bring =
>others that aren't as mechanical into the airplane building business. It =
>may also find its way into a factory built composite that is affordable =
>to a larger group of people.

Last spring I interviewed with a company that builds automation
equipment for manufacturing.  The have gantry robots that MacDac uses
building F-18's and a large X-Y table used for cutting stuff. The end
effector used will determine what they cut, and the quality of the
results. 

The most popular end effector was a waterjet. At > 50Kpsi, it'll cut
granite, or foam, with amazing prescision.  Several of their customers
cut foam plugs that the boat manufacturers use for fiberglass
molds. Most of the boat manufacturers use a bullnose cutter, but water
does work for long straight cuts.

Date: Fri, 26 Mar 1999 08:07:16 +0200
From: "Rego Burger" <BurgerR@telkom.co.za>
Subject: COZY: Laser cut foam cores

In reply to NAt's comments on doing them yourself....

I found foam cutting fun...one of the few taskes my wife liked to help
with...... besides the cost saving ( free labour ) the accuracy of lazer
cutting does not = the cost.



Rego Burger
RSA

From: Todd Carrico <todd.carrico@aris.com>
Subject: RE: COZY: foam cores
Date: Fri, 26 Mar 1999 07:29:53 -0800

I used to work in the Die Cutting industry.  They use lasers to make the
boards they set the knives in.  Basically the laser beam is about 3 inches
in diameter until it reaches the cutting head.  Then it is "Focused" at the
center thickness of the board.  That is the thinnest part of the kerf.  the
kerf grows from that point up and down.  This would not be very good way to
cut a long (anything over 6") foam core.  I also have allot of experience
with Water jet technology, and they have a worse problem.  We used Styro
Foam as a bed material (Whatever you use as a bed is destroyed).  After the
water penetrates the first layer the stream "Diffuses".  We cut some pretty
thick stuff for a Water Jet at 6" also, but the finish stank, and the
tolerances were horrible.

The only problem that I am aware of with the hot wire saw is the tendency
for the wire to lag.  This can cause a sag in the middle of the part, and
funny looking corners.  If you were to manufacture a hand held Band Saw (It
is possible, you would not need that much power, and you could undersize
your templates and use a guide that follows your template) you might get
away from the sag, but you would have a tough time making the Spar trough,
and the other "sharp" (for a bandsaw) corners.

The Hot wire saw is just the best tool for the job.  Even this Laser machine
was just a Hot Wire saw driven by step motors, and hooked to a PC.  I agree
that we are trying to do things better, but we also need to keep from
re-inventing the hot wire saw (er wheel)

tc
-----Original Message-----
From: Ron Larock [mailto:rlarock@mediaone.net]
Sent: Thursday, March 25, 1999 5:38 PM
To: Cozy_Builders@canard.com
Subject: COZY: foam cores


Dear List,
 
I know that cutting cores with a hot wire is very accurate, but I would
think that finding new and possibly more accurate ways of doing things is
also what we are about. If a lazer can cut the foam to a much higher degree
of accuracy and faster, maybe this group may have found a way to make
building composite airplanes faster and cheaper. It may bring others that
aren't as mechanical into the airplane building business. It may also find
its way into a factory built composite that is affordable to a larger group
of people.
 
Ron
 
 

From: Militch@aol.com
Date: Tue, 3 Aug 1999 22:11:40 EDT
Subject: COZY: Foam color change

I have my fuselage tub sitting on a couple of sawbenches in the garage, with 
the bulkheads installed. Work has interrupted building for a few weeks, so 
the tub has been out there post-curing (we have had 100 degree humid days, 
and the garage can get quite a bit warmer than outside).  I noticed last 
night when I glanced at the tub that the sheet of foam I used at the rear on 
each fuselage side has turned from blue to purple.  A closer look reveals the 
same color change just starting to fade in on the sheets used in the middle 
and at the front.  The foam's texture seems unchanged, and it doesn't appear 
to be powdered, or otherwise altered.  I have observed some slight color 
changes on scrap pieces of similar foam left lying under the fluorescent 
lights in my basement workshop, but the garage has generally been in the 
dark. I haven't tried scuffing it with sandpaper to see if the change is just 
surface discoloration. Has anyone else experienced this?

Peter Militch Cozy Mark IV Chapter 6

Date: Wed, 04 Aug 1999 06:04:55 -0400
From: Jeff Russell <JRaero@gte.net>
Subject: Re: COZY: Foam color change



Militch@aol.com wrote:

>  Has anyone else experienced this?
>
> Peter Militch Cozy Mark IV Chapter 6

This is normal for the PVC to darken with any light.

--
Jeff Russell/AeroCad Inc.                    E-mail:   Jeff@aerocad.com
2954 Curtis King Blvd.  Ft. Pierce, FL. 34946
Shop# 561-460-8020 7:00am to 3:30pm  Home# 561-344-6200
Website:   http://www.Aerocad.com
Composite workshop info:   http://www.Sportair.com


Date: Tue, 03 Aug 1999 23:03:16 -0400
From: "Marc J. Zeitlin" <marcz@ultranet.com>
Subject: Fwd: COZY: Foam color change

Pete Militch asks:

>..... I haven't tried scuffing it with sandpaper to see if the change is just 
>surface discoloration. Has anyone else experienced this?

Short answer? Yes.  This has been discussed and is in the archives.  It's
caused by exposure to UV, and does NOT seem to affect the properties of the
foam - you just get some discoloration.

--
Marc J. Zeitlin           mailto:marcz@ultranet.com
                          http://www.ultranet.com/~marcz/

Date: Wed, 20 Oct 1999 18:34:22 -0500
From: Bulent Aliev <atlasyts@bellsouth.net>
Subject: Re: COZY: Foam Required

That's why I did mine the two step way. Cut them oversize and not wary about
the burns, than sand them down to shape. It worked the second time for me. The
first time I used the wrong template on the bottom, so I ended with very
skinny winglet cores. I knew that something was wrong and went to another
builder's hangar to show them and he discovered my mistake.
Bulent

Epplin John A wrote:

> Also made one of the vertical fins twice, they are hard to get really good,
> the difference in sections from the root to tip is not good, hard to keep
> from melting too far into the tip end.
>
>         John epplin...


From: "Alpha" <alpha@concordnc.com>
Subject: COZY: Foam
Date: Sat, 23 Oct 1999 12:34:05 -0400

Fellow builders,

There is a foam fabricator (custom cuts foam into various sizes)  that I
pass twice a day.  I talked to him a while back and got some foam samples
(styrofoam) that appear to be the same as ACS/Wicks product.  He gets the
styrofoam and urethane in large billets.  To save costs in shipping, and
perhaps the cost of the foam, I would like to know if anyone can tell me the
exact manufacturers (ie. Dow et al) parts numbers for the styrofoam and
urethane.  I know there is supposed to be a difference in the styrofoam
bubble size in the 2 lb/ft^3 product thus for the need for product numbers.
I want to get started building with the right stuff but I need to save all
the cash I can....my son turns 16 tomorrow and you know how much teenagers
can cost!!!  Can anyone help?

Jim Brewer
Albemarle, NC

From: Militch@aol.com
Date: Fri, 24 Dec 1999 14:08:44 EST
Subject: COZY: Use of pour foam

There was an article in the last newsletter about using pour foam to form the 
leading edges of the strakes.  I recently downloaded the electronic version 
of the old Canard Pushers and have been reading them from issue 1.  Somewhere 
in there was a comment by Burt Rutan regarding a large pour foam assembly 
someone tried.  Might have been a wing, but I am not sure. Anyway, he 
reported that the builder experienced blistering of the wing afterward and 
attributed it to the foam's properties when exposed to the heat of Summer.  
Has the composition of pour foams changed enough in the last 10 or 20 years 
to make it useful for large parts, or is that still likely to be a problem?  
I think Chris Scida used pour foam to make his nose assembly, and that seemed 
pretty good when I saw it recently.

Regards,
  Peter Militch #740

From: cdenk@ix.netcom.com
Date: Fri, 24 Dec 1999 15:46:07 -0500 (EST)
Subject: Re: COZY: Use of pour foam

For sure, don't use pour foam any place exposed to more than low to moderate temps. I used it to make a stiffening rib, max. 
1/2" thick on my top and bottom cowls. At both areas the foam expanded creating a bulge in the cowl surface. This was both top 
and bottom, where the bottom heat isn't very high. I would be very careful where used, not any big flat surfaces, or too 
thick.

